如何制作Javafx图像裁剪应用程序
我正在为我的同事构建一个裁剪图像的应用程序。如何制作Javafx图像裁剪应用程序,java,image,canvas,graphics,javafx,Java,Image,Canvas,Graphics,Javafx,我正在为我的同事构建一个裁剪图像的应用程序。 我使用FXML和场景生成器来构建GUI。用户单击按钮从计算机中选择图像。然后,图像显示在GUI中。用户可以在窗格中缩放和移动。最后,单击一个按钮将编辑后的图像保存到他的计算机中。然而,我真的不知道应该使用哪个库来构建应用程序。这是我第一次处理图形。我不知道如何读取图像、裁剪图像和写入图像。对于窗格?除了java文档之外,还有什么好的资源可以阅读,以了解如何执行此操作?关于StackOverflow,您的问题太多了,无法回答。我建议你从阅读这本书开始
我使用FXML和场景生成器来构建GUI。用户单击按钮从计算机中选择图像。然后,图像显示在GUI中。用户可以在窗格中缩放和移动。最后,单击一个按钮将编辑后的图像保存到他的计算机中。
然而,我真的不知道应该使用哪个库来构建应用程序。
这是我第一次处理图形。我不知道如何读取图像、裁剪图像和写入图像。对于窗格?
除了java文档之外,还有什么好的资源可以阅读,以了解如何执行此操作?关于StackOverflow,您的问题太多了,无法回答。我建议你从阅读这本书开始 然而,由于这是一个有趣的话题,下面是代码中的答案 您需要考虑以下几点:
- 将ImageView用作容器
- 如果图像较大,请使用滚动窗格
- 提供选择机制
- 裁剪图像本身
- 将图像保存到文件,提供文件选择器对话框
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Bounds;
import javafx.geometry.Rectangle2D;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.control.ScrollPane;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.StrokeLineCap;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
import javax.imageio.ImageIO;
/**
* Load image, provide rectangle for rubberband selection. Press right mouse button for "crop" context menu which then crops the image at the selection rectangle and saves it as jpg.
*/
public class ImageCropWithRubberBand extends Application {
RubberBandSelection rubberBandSelection;
ImageView imageView;
Stage primaryStage;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
this.primaryStage = primaryStage;
primaryStage.setTitle("Image Crop");
BorderPane root = new BorderPane();
// container for image layers
ScrollPane scrollPane = new ScrollPane();
// image layer: a group of images
Group imageLayer = new Group();
// load the image
// Image image = new Image( getClass().getResource( "cat.jpg").toExternalForm());
Image image = new Image("https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Gatto_europeo4.jpg/1024px-Gatto_europeo4.jpg");
// the container for the image as a javafx node
imageView = new ImageView( image);
// add image to layer
imageLayer.getChildren().add( imageView);
// use scrollpane for image view in case the image is large
scrollPane.setContent(imageLayer);
// put scrollpane in scene
root.setCenter(scrollPane);
// rubberband selection
rubberBandSelection = new RubberBandSelection(imageLayer);
// create context menu and menu items
ContextMenu contextMenu = new ContextMenu();
MenuItem cropMenuItem = new MenuItem("Crop");
cropMenuItem.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
// get bounds for image crop
Bounds selectionBounds = rubberBandSelection.getBounds();
// show bounds info
System.out.println( "Selected area: " + selectionBounds);
// crop the image
crop( selectionBounds);
}
});
contextMenu.getItems().add( cropMenuItem);
// set context menu on image layer
imageLayer.setOnMousePressed(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
if (event.isSecondaryButtonDown()) {
contextMenu.show(imageLayer, event.getScreenX(), event.getScreenY());
}
}
});
primaryStage.setScene(new Scene(root, 1024, 768));
primaryStage.show();
}
private void crop( Bounds bounds) {
FileChooser fileChooser = new FileChooser();
fileChooser.setTitle("Save Image");
File file = fileChooser.showSaveDialog( primaryStage);
if (file == null)
return;
int width = (int) bounds.getWidth();
int height = (int) bounds.getHeight();
SnapshotParameters parameters = new SnapshotParameters();
parameters.setFill(Color.TRANSPARENT);
parameters.setViewport(new Rectangle2D( bounds.getMinX(), bounds.getMinY(), width, height));
WritableImage wi = new WritableImage( width, height);
imageView.snapshot(parameters, wi);
// save image
// !!! has bug because of transparency (use approach below) !!!
// --------------------------------
// try {
// ImageIO.write(SwingFXUtils.fromFXImage( wi, null), "jpg", file);
// } catch (IOException e) {
// e.printStackTrace();
// }
// save image (without alpha)
// --------------------------------
BufferedImage bufImageARGB = SwingFXUtils.fromFXImage(wi, null);
BufferedImage bufImageRGB = new BufferedImage(bufImageARGB.getWidth(), bufImageARGB.getHeight(), BufferedImage.OPAQUE);
Graphics2D graphics = bufImageRGB.createGraphics();
graphics.drawImage(bufImageARGB, 0, 0, null);
try {
ImageIO.write(bufImageRGB, "jpg", file);
System.out.println( "Image saved to " + file.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
graphics.dispose();
}
/**
* Drag rectangle with mouse cursor in order to get selection bounds
*/
public static class RubberBandSelection {
final DragContext dragContext = new DragContext();
Rectangle rect = new Rectangle();
Group group;
public Bounds getBounds() {
return rect.getBoundsInParent();
}
public RubberBandSelection( Group group) {
this.group = group;
rect = new Rectangle( 0,0,0,0);
rect.setStroke(Color.BLUE);
rect.setStrokeWidth(1);
rect.setStrokeLineCap(StrokeLineCap.ROUND);
rect.setFill(Color.LIGHTBLUE.deriveColor(0, 1.2, 1, 0.6));
group.addEventHandler(MouseEvent.MOUSE_PRESSED, onMousePressedEventHandler);
group.addEventHandler(MouseEvent.MOUSE_DRAGGED, onMouseDraggedEventHandler);
group.addEventHandler(MouseEvent.MOUSE_RELEASED, onMouseReleasedEventHandler);
}
EventHandler<MouseEvent> onMousePressedEventHandler = new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
if( event.isSecondaryButtonDown())
return;
// remove old rect
rect.setX(0);
rect.setY(0);
rect.setWidth(0);
rect.setHeight(0);
group.getChildren().remove( rect);
// prepare new drag operation
dragContext.mouseAnchorX = event.getX();
dragContext.mouseAnchorY = event.getY();
rect.setX(dragContext.mouseAnchorX);
rect.setY(dragContext.mouseAnchorY);
rect.setWidth(0);
rect.setHeight(0);
group.getChildren().add( rect);
}
};
EventHandler<MouseEvent> onMouseDraggedEventHandler = new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
if( event.isSecondaryButtonDown())
return;
double offsetX = event.getX() - dragContext.mouseAnchorX;
double offsetY = event.getY() - dragContext.mouseAnchorY;
if( offsetX > 0)
rect.setWidth( offsetX);
else {
rect.setX(event.getX());
rect.setWidth(dragContext.mouseAnchorX - rect.getX());
}
if( offsetY > 0) {
rect.setHeight( offsetY);
} else {
rect.setY(event.getY());
rect.setHeight(dragContext.mouseAnchorY - rect.getY());
}
}
};
EventHandler<MouseEvent> onMouseReleasedEventHandler = new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
if( event.isSecondaryButtonDown())
return;
// remove rectangle
// note: we want to keep the ruuberband selection for the cropping => code is just commented out
/*
rect.setX(0);
rect.setY(0);
rect.setWidth(0);
rect.setHeight(0);
group.getChildren().remove( rect);
*/
}
};
private static final class DragContext {
public double mouseAnchorX;
public double mouseAnchorY;
}
}
}
导入java.awt.Graphics2D;
导入java.awt.image.buffereImage;
导入java.io.File;
导入java.io.IOException;
导入javafx.application.application;
导入javafx.embed.swing.SwingFXUtils;
导入javafx.event.ActionEvent;
导入javafx.event.EventHandler;
导入javafx.geometry.Bounds;
导入javafx.geometry.Rectangle2D;
导入javafx.scene.Group;
导入javafx.scene.scene;
导入javafx.scene.Snapshot参数;
导入javafx.scene.control.ContextMenu;
导入javafx.scene.control.MenuItem;
导入javafx.scene.control.ScrollPane;
导入javafx.scene.image.image;
导入javafx.scene.image.ImageView;
导入javafx.scene.image.WritableImage;
导入javafx.scene.input.MouseEvent;
导入javafx.scene.layout.BorderPane;
导入javafx.scene.paint.Color;
导入javafx.scene.shape.Rectangle;
导入javafx.scene.shape.StrokeLineCap;
导入javafx.stage.FileChooser;
导入javafx.stage.stage;
导入javax.imageio.imageio;
/**
*加载图像,提供矩形以便选择橡胶带。按鼠标右键“裁剪”上下文菜单,然后在选择矩形处裁剪图像并将其保存为jpg。
*/
公共类ImageCropWithRubberBand扩展了应用程序{
橡皮筋选择橡皮筋选择;
图像视图图像视图;
初级阶段;
公共静态void main(字符串[]args){
发射(args);
}
@凌驾
公共无效开始(阶段primaryStage){
this.primaryStage=primaryStage;
初级阶段。设置标题(“图像裁剪”);
BorderPane根=新的BorderPane();
//图像层的容器
ScrollPane ScrollPane=新的ScrollPane();
//图像层:一组图像
Group imageLayer=新组();
//加载图像
//Image Image=newimage(getClass().getResource(“cat.jpg”).toExternalForm());
图像=新图像(“https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Gatto_europeo4.jpg/1024px-Gatto_europeo4.jpg");
//作为javafx节点的图像容器
imageView=新的imageView(图像);
//将图像添加到图层
imageLayer.getChildren().add(imageView);
//如果图像较大,请使用滚动窗格查看图像
scrollPane.setContent(imageLayer);
//在场景中放置滚动窗格
root.setCenter(滚动窗格);
//橡胶带选择
rubberBandSelection=新的rubberBandSelection(imageLayer);
//创建上下文菜单和菜单项
ContextMenu ContextMenu=新建ContextMenu();
MenuItem cropMenuItem=新MenuItem(“作物”);
setOnAction(新的EventHandler()){
公共无效句柄(ActionEvent e){
//获取图像裁剪的边界
Bounds selectionBounds=rubberBandSelection.getBounds();
//显示边界信息
System.out.println(“所选区域:+selectionBounds”);
//裁剪图像
裁剪(选择边界);
}
});
contextMenu.getItems().add(cropMenuItem);
//设置图像层上的关联菜单
setOnMousePressed(新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
if(event.isSecondaryButtonDown()){
show(imageLayer,event.getScreenX(),event.getScreenY());
}
}
});
设置场景(新场景(根,1024768));
primaryStage.show();
}
私有无效裁剪(边界){
FileChooser FileChooser=newfilechooser();
setTitle(“保存图像”);
File File=fileChooser.showsavedilog(primaryStage);
if(file==null)
返回;
int width=(int)bounds.getWidth();
int height=(int)bounds.getHeight();
SnapshotParameters=新的SnapshotParameters();
参数。设置填充(颜色。透明);
parameters.setViewport(新的矩形2D(bounds.getMinX(),bounds.getMinY(),width,height));
WritableImage wi=新的WritableImage(宽度、高度);
imageView.snapshot(参数,wi);
//保存图像
//!!!由于透明性而存在错误(使用下面的方法)!!!
// --------------------------------
//试一试{
//write(SwingFXUtils.fromFXImage(wi,null),“jpg”,文件);
//}捕获(IOE异常){
//e.printStackTrace();
// }
//保存图像(不带alpha)
// --------------------------------
BuffereImage bufImageARGB=SwingFXUtils.fromFXIm